Process of separating cellulose esters from solutions.



LEONHARD LEDERER, OF SULZBACH, GERMANY.

PROCESS OF SEPARATING CELLULOSE ESTERS FROM SOLUTIONS.

Specification 01 Letters Patent.

Patented Oct. 27, 1908.

Application filed November 24, 1906. Serial No. 344,867.

To all whom it may concern:

Be it known that I, LEONHARD LEDERER, a subject of the German Emperor,residing at Sulzbach, Germany, have invented a certain new and usefulProcess for Separating Cellulose Esters from Solutions, of which thefollowing is a specification.

If cellulose is esterized by means of acid anhydrid or acid chlorid, theproduct of the reaction is usually not obtained in a solid form, but inthe shape of solutions, from which thecellulose esters must beseparated. For this purpose liquids, such as water and alcohol, which donot dissolve cellulose, may be used, or if it is desired to recover atthe same time unaltered acid anhydrid or the acid which has been formedby the reaction or added as a diluent, benzene and similar compounds maybe employed instead of water or alcohol. I have found, that for thelatter purpose carbon tetra-chlorid is eminently suitable, because itwill not dissolve any of the cellulose esters obtained by the methods ofmanufacture hitherto known, and is generally applicable for theseparation of the same, besides being unimflammable, and because itsboiling oint is substantially diflerent from that o the acid anhydridand the acid arising during the reaction or added for dilution, whichfacilitates the separation of the mixture composed of these bodies.

The use of carbon tetra-chlorid renders it practicable, to effect theseparation of the mass produced by the esterfication in openreceptacles, and consequently to dispense with special apparatus.

In View of the fact, that substances similar to carbon-tetra-chlorid,such as chloroform,

ethane tetra-chlorid and dichlorhydrin, are

Example: The iquid to be treated may be,

for instance, the product of the reaction produced by acetylizingcellulose with acetic anhydrid. Carbon tetra chlorid is added, Whilecarefully stirring, until a thick uniform paste has been formed. Thepaste is pressed, and if necessary the solid residue is again stirredwith tetra-chlorid and the mixture treated in the manner described.

What I claim is:

1. The process for obtaining cellulose es ters from solutions of thesame, which (011' sists in intimately intermingling carbontetrachloridwith the solution until a paste is formed, and then subjectin theproduct to mechanical separation, su stantially as described.

2. The rocess for obtaining cellulose esters from iquid acidylizingmixtures, which consists in intimately intermingling carbon tetrachloridwith the mixture until a paste is formed, and then subjecting theproduct to mechanical separation, substantially as described.

In testimony whereof I have set my hand he'reunto in the presence of twosubscribing witnesses.

KARL SHAEFER, J r., CARL SINGER.

